Odd file transfer behavior - k750i/w800i

[SB118]

I'm running a w800i flashed k750i and i'm having trouble transfering files and getting them to stay put once they are transfered!

I can copy files (mp3s) over quite happily, i can check the properties of the files, i can browse the rest of my computer, then go back to the phone and recheck the files.

But once i unplug the phone a lot of the files disappear. When i plug in to the computer again the files don't show up anymore.

Any ideas?

 

[SB118]

Nobody else had this? I'm copying over whole albums, browsing them on the PC, then finding they've disappeared when i try and play them on the phone